1. Field of the Invention
This invention relates to an electromagnetic device and more particularly to automatic relays and the like.
2. Prior Art
Electromatic relays which interpose a rigid slide member mounted in a slide guide between an armature and one or more contact springs of a relay assembly are known.
For various reasons, in electromagnetic relays of the above described type, the armature is often constructed to have relatively friction free movement. In this manner, designers have attempted to achieve the lowest possible actuation power requirements while simultaneously achieving the highest possible switching speed. Additionally, by reducing friction, it is possible to reduce contamination of the relay contacts by reducing abrasion caused contaminents. The result has been to provide an increased life span.
However, in certain cases, the use of extremely low friction armature mounting designs leads to undesirably severe contact chattering which can occur when the armature and the rigid member return together to a rest position after the switching movement has occurred. Such chatter is not caused solely by the recall of the armature but, to a certain extent, is caused or added to by natural oscillations of the slide and the relay contact spring.
It has been known to damp such oscillation movement of the armature by means of interposed partially elastic stops. Such a construction is shown in German Auslegeschrift No. 1,917,896. In other embodiments, friction springs have been provided with the springs rubbing directly on the relay contact spring to reduce or nullify any undesired excess kenetic energy. See British Pat. No. 1,142,904 for such a construction.
The known chatter damping devices have a common disadvantage in that they require additional parts and assembly operations. Additionally when used in relays which utilize a rigid slide carried member, such devices are of reduced utility in that they fail to sufficiently dampen chatter caused by or attributable to the mass of the rigid member.
It would therefore be an advance in the art to provide a method of reducing or eliminating chatter in electromagnetic relays of the type having a rigid slide member interposed and guided between an armature and a portion of the relay for transmitting the armature movement to the relay.